Amnesia: The Dark Descent

Apparently something went wrong on the previous update, making it a bit difficult to run total conversion mods out of the box. Version 1.311 addresses that issue so you don't have to hack stuff to make them work.

Changelist:
- Launcher checks for the 'DefaultMainSettingsSDL2' entry in the init config file passed as argument and falls back to the game's default if not present.
- Game checks for the 'DefaultMainSettingsSDL2' and 'DefaultUserKeysSDL2' entries in the init config file passed as argument and falls back to the game's default if not present.
- Added "steam_appid.txt" file to make it possible to run the game exe outside Steam.